In a tape player such as video deck, digital audio tape player, etc. configured to wind a tape on a rotary head to play the tape, it is necessary that the tape contacts the rotary head under a constant pressure in a play mode.
As a tape tension mechanism for this purpose, there is an arrangement using a pivotable tension member biased by a spring force into contact with a tape surface to control movements of a supply reel in response to the pivoting position of the tension member. Such a tension member was positioned at an outer side of the tape path in old prior art devices. However, from the standpoint of reducing the size of the mechanism, a recently proposed arrangement positions it at an inner side of the tape path so that it moves ahead together with a tape loading block upon a tape loading operation.
In the above-indicated arrangement where the tension member is located in an inner side of the tape path, it requires the following different controls in play, stop and fast-winding modes.
That is, in the play mode, a biasing force of a spring is required in order to hold the tension member in contact with a tape under a constant pressure. In the stop mode, the tension member must be released in a direction away from the tape, slightly and not fully, because if it is released fully, it will get off a tape lead of the rotary head. Also in the fast-winding mode, the tension member must be released slightly. However, since the tension force in the fast-winding mode is larger than in the play mode and often overcome the energy of the spring for the tension member and therefore permits the tension member to rotate largely. In order to prevent the phenomenon a further control of the pivoting amount of the tension member is required.
However, in order to effect such different controls it is necessary to not only use a number of additional parts such as element for driving the tension member in the released direction in a certain mode, element for locking the tension member at a position, element for unlocking it from the position, etc. but also adjust motion timings of respective elements. Therefore, this invites an increase in the number of parts and a complicated structure.